The invention relates to an hydraulically-damped mount and, more particularly, an engine mount for a motor vehicle.
An hydraulically-damped engine mount is known from U.S. Pat. No. 2,387,066. In it, a resilient pad or element directly bounds a working space for the hydraulic fluid. When high frequency vibrations are introduced, therefore, dynamic induration (hardening) can occur with the vibrations then being transmitted through the engine mount. In a motor vehicle, in particular example, such vibrations from the engine can be a great nuisance in the form of throbbing in the vehicle.
Also in the hydraulic mount described in the patent reference above, initial-movement-delimiting bumper shoulders and counter shoulders are in the working space for the hydraulic fluid and sweep a large enough volume of the fluid with their relative motion in response to vibrations to impair their relative mobility and, thus, the damping. This also churningly stresses the hydraulic fluid. The noise of so accelerating the hydraulic fluid, including, possibly, from cavitation, can also be a nuisance in some applications. Still another disadvantage is that changes in the contours of the resilient pad defining part of the hydraulic fluid space with the motion to be damped may decrease the desired hydraulic damping significantly. For example, such motional changes in the shape of local cavities in the pad which are provided for setting its rigidity (resilient damping) in transverse or other directions can do this.